1. Field Of The Invention
The present invention relates generally to blender apparatus, and particularly to a blender apparatus mounted upon a movable vehicle.
2. Description Of The Prior Art
Many activities conducted in connection with the servicing of oil wells involve the blending of one or more solid particulate materials with a liquid which is to be pumped down into a well.
Most such equipment is designed for relatively large jobs requiring the production of up to as much as 100 barrels per minute (BPM) of blended fluid, and utilize at least two pumps, one to deliver base fluid to the blender and another to pump the blended fluid away from the blender. Typical prior art blenders also often require more than one human operator.
A relatively recent development by the assignee of the present invention is the constant level additive mixing system disclosed in U.S. Pat. No. 4,490,047 to Stegemoeller et al. The Stegemoeller system utilizes a single pump to both draw clean fluid from a fluid supply and draw blended fluid from a relatively small capacity blender. A first portion of the fluid is then recirculated back to the blender, while a second portion is discharged to high pressure pumps which pump the blended fluid down into a well.
The Stegemoeller et al. '047 system also introduces the concept of an automatic leveling device for controlling the level of the fluid in the blender tub.
The particular system disclosed in Stegemoeller et al. was designed to be hung on the side of a vehicle such as an acidizing truck, so that the blender could be utilized to mix various additives with the acids which were to be pumped downhole.
The tub assembly shown in the Stegemoeller et al. '047 patent has also been used by the assignee of the present invention on the rear of a fracturing truck. In that assembly, the tub was fixed to the rear of the truck and did not move other than to rotate upon its torsion bar.